Flutter云函数调用插件cloud_functions的使用

Firebase Cloud Functions for Flutter

这是一个用于在Flutter中使用Firebase Cloud Functions API的插件。要了解更多关于Cloud Functions的信息，请访问Firebase官网。

Getting Started

开始使用Firebase Cloud Functions，请参考官方文档。

Usage

要使用此插件，可以参考Functions Usage文档。

Issues and feedback

如果您遇到与FlutterFire相关的问题、错误或有功能需求，请在我们的问题跟踪器上提交。对于不是特定于FlutterFire的插件问题，可以在Flutter问题跟踪器上提交。若想为插件贡献代码，请先阅读我们的贡献指南，然后打开一个pull request。

示例代码

以下是一个完整的示例demo，展示了如何在Flutter应用中使用cloud_functions插件来调用云端函数：

// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:core';
import 'dart:io';

import 'package:cloud_functions/cloud_functions.dart';
import 'package:cloud_functions_example/firebase_options.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await Firebase.initializeApp(
    options: DefaultFirebaseOptions.currentPlatform,
  );

  // 如果您需要使用本地运行的Functions Emulator，请取消下面这行的注释
  // https://firebase.google.com/docs/functions/local-emulator
  // FirebaseFunctions.instance.useFunctionsEmulator('localhost', 5001);

  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  List fruit = [];

  @override
  Widget build(BuildContext context) {
    final localhostMapped =
        kIsWeb || !Platform.isAndroid ? 'localhost' : '10.0.2.2';

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Firebase Functions Example'),
        ),
        body: Center(
          child: ListView.builder(
            itemCount: fruit.length,
            itemBuilder: (context, index) {
              return ListTile(
                title: Text('${fruit[index]}'),
              );
            },
          ),
        ),
        floatingActionButton: Builder(
          builder: (context) {
            return Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.end,
              children: [
                FloatingActionButton.extended(
                  onPressed: () async {
                    HttpsCallable callable =
                        FirebaseFunctions.instance.httpsCallable(
                      'listFruit',
                      options: HttpsCallableOptions(
                        timeout: const Duration(seconds: 5),
                      ),
                    );

                    await callingFunction(callable, context);
                  },
                  label: const Text('Call Function'),
                  icon: const Icon(Icons.cloud),
                  backgroundColor: Colors.deepOrange,
                ),
                const SizedBox(height: 10),
                FloatingActionButton.extended(
                  onPressed: () async {
                    HttpsCallable callable =
                        FirebaseFunctions.instance.httpsCallableFromUrl(
                      'http://$localhostMapped:5001/flutterfire-e2e-tests/us-central1/listfruits2ndgen',
                      options: HttpsCallableOptions(
                        timeout: const Duration(seconds: 5),
                      ),
                    );

                    await callingFunction(callable, context);
                  },
                  label: const Text('Call 2nd Gen Function'),
                  icon: const Icon(Icons.cloud),
                  backgroundColor: Colors.deepOrange,
                ),
              ],
            );
          },
        ),
      ),
    );
  }

  Future<void> callingFunction(
    HttpsCallable callable,
    BuildContext context,
  ) async {
    try {
      final result = await callable();
      setState(() {
        fruit.clear();
        result.data.forEach((f) {
          fruit.add(f);
        });
      });
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('ERROR: $e'),
        ),
      );
    }
  }
}

关键点解释

• 初始化Firebase：在main()函数中使用await Firebase.initializeApp(...)来初始化Firebase。
• 使用Functions Emulator（可选）：如果需要使用本地运行的Firebase Functions模拟器，可以通过FirebaseFunctions.instance.useFunctionsEmulator('localhost', 5001);进行设置。
• 调用云端函数：通过HttpsCallable对象调用云端函数，并通过callingFunction方法处理结果和异常。
• UI更新：根据云端函数返回的结果更新UI显示的内容。

以上就是关于Flutter云函数调用插件cloud_functions的基本介绍和使用示例，希望对您有所帮助！